Electric resistance unit



Jan. 1, 1929. 1,697,406

H. G. RICHTER ELECTRI C RES I S TANCE UNIT Filed Dec. 1'7, 192'? IN V EN TOR.

W TTORiVEY Patented Jan. 1, 1929.

UNITED STATES PATENT OFFICE.

HENRY G. RICHTER, F ROSELLE PARK, NEW JERSEY, ASSIGNOR '.I.O ELECTRAD, INC.

I OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

' ELECTRIC RESISTANCE UNIT.

Application filed December 17, 1927. Serial No. 240,874.

My invention relates broadly to electrical resistors and more particularly to a construction of an electrical resistance element.

One of the objects of my invention is to provide a construction of electrical resistance element wherein a relatively high resistancemay be obtained within a relatively short length.

Another object of my invention is to provide a construction of electrical resistance provide a construction of electrical resistor wherein a flexible metallic core is provided with a covering of insulation over 'which a resistance wire element is spirally wound and connected to terminals carried by opposite ends of said flexible core with an envelope of insulated material secured over the resistance element by means of the terminals at opposite ends of the resistor.

My invention will be more clearly understood from the specification-hereinafter following by reference to the accompanying drawings, wherein:

Figure l is a plan view of an electrical resistor embodying the principles of my invention; Fig. 2 is a side View ofthe electrical resistor showing the construction of the device of my invention; Fig. 3 is an enlarged fragmentary view partially in cross-section showing the arrangement of the. resistance .elemcnt over the insulated envelope and the arrangement of the terminal at one end of the resistor in electrical connectlon with the resistance element; Fig. 4 1s an enlarged crosssectional view taken .through the resistor of cast receiving'apparatus to provide permanent values of resistance in selected parts of the electrical circuits of amplification systems.- The available space in which such resistance elements may be placed is'often very small and it is the purpose of my invention to provide that kind of high resistance element which may be located within a small available area adjacent the other parts of the electrical apparatus constituting an amplifier system. The construction of the resistor of my invention is such that the resistor may be readily bent upon itself after assembly and compacted to such a size that it may fit within the small available space.

Referring to the drawings in more detail, reference character 1 designates a flexible core structure over which an envelope 2 of insulated material is wrapped. The envelope 2 may be formed from any suitable heat resisting insulation such as asbestos. The core 1 may be a flexible copper wire enameled on its surface to provide an insulated coating 'in cooperation with the insulated wrapping 2. A high resistance wire 3 is spirally wound over the insulated wrapping 2 with the turns thereof very close together. By reason of the close windingof the turns, an extremely high resistance may be obtained per unit of length. I have obtained Values of 600 to 1,000 ohms to the inch in a flexible resistor constructed in accordance with my invention. The resistance wire element is normally so fine that it is difficult to see a single strand with the naked eye and the resistor has the appearance of a continuous metal coating instead of the individual spirally wound turns of high resistance wire. The assembly of core structure, insulated covering and fine wire winding is encased in insulated tubing represented at 4. At opposite ends of the resistor, I provide terminals designated at 5 and 6. Terminal 5 is pro vided with lugs 9 and 10 which grip over the fine wire 3 and over the insulated tubing 4, respectively, and are secured against withdrawal by means of the hook 7 formed on the end of the core member 1. The opposite end of core member 1 extends beyond the insulation covering-2 and is formed into a hook 8 which retains terminal 6 by means of lugs 11 and 12. The lug 11 is secured over the insulated tubing 4, while the lug 12 fastens over and establishes connection to the fine wire member 3. The hooks 7 and 8 prevent Withdrawal of the terminals 5 and 6 from opposite ends of the resistor. The

" resistor is flexible in character and may be the coil.

- lows I have found the resistance element of my invention extremely practical for purposes of manufacture and production on a quantity production basis, and while I have described my invention in certain of its preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other. than are imposed by the sco )e'of the appended claims.

hat Iclaim as new and desire to secure by Letters Patent of the United States is as fol- 1. A resistor comprising a'flexible metallic core, an insulated coating for said core, a resistance wire spirally wound over said coat: ing, an insulated envelope positioned over said resistance wire, terminal members at opposite ends of said resistor, said terminal members being constituted by lugs some of which engage hook shaped ends on said core member and establish an electrical connection with opposite ends of said resistance wire and others of which engage said insulated envelopepositioned over said resistance wire for maintaining said envelope in position over said resistance wire. I

2. Aresistor comprising flexible metallic core,'an insulated covering for said flexible metallic core, a resistance wire spirally wound upon said insulatedcovering, an insulated tubing fitting over said resistance wire and hooks formed on opposite ends of said flexible metallic core engaging terminals at each end thereof and establishing an electrical connection with opposite ends of said resistance wire, said terminals embracing the ends of said insulated tubing and maintaining said tubing in position over said resistance wire.

3, A resistor comprisin a flexible metallic core member, an insu ated covering. positioned upon said core member, a resistance wire spirally wound over said insulated covering, a flexible tubing of insulated material fitting over said wire, hook shaped ends on said core and terminals engaging each of the hook shaped ends on said corc, portions of said terminals being secured over the insulated covering and other portions of said terlninals bein secured over said resistance wire for establishing an electrical connection therewith. Y

4. An electrical resistor comprising a flexible metallic core, a wrapping of flexible insulation material formed on said core, a re- .sistance wire element spirally wound upon said wrapping of flexible insulation material, a flexible insulated tubing enveloping said resist-ance wire element and the insulated covering and flexible core on which said element is disposed, terminal members at the ends of said resistors comp-rising clips provided with separate pairs of lugs, one pair of said lugs engaging the resistance wire element upon ent sets of lugs, one set of said lugs engaging said resistance wire element over said core member and another of saidsets of lugs engaging said insulated tubing for sealing said resistance wire element within said insulated tubing.

' HENRY G. RICHTER. 

